It is well known to provide ventilation to enclosed spaces of buildings, such as crawl spaces and basements, by the use of ventilators located in openings of the foundation walls. Such ventilators are generally provided with adjustable closure means, such as shutters or louvers, to control the flow of air to and from the enclosed space, depending on temperature, weather conditions or seasonal changes. Generally such foundation wall ventilators are secured in the wall opening during construction of the foundation wall by cement, mortar, or other fastening materials.
It is also known to provide temperature responsive control of the closure shutters or louvers of such ventilators by the use of bimetallic temperature responsive springs which may be operatively connected between the fixed housing of the ventilator and the movable shutters in such a way that expansion or contraction of the springs due to temperature changes causes pivotal movement of the shutters from open to closed positions in the air flow passageway through the ventilator housing. Typical of such devices are disclosed in the following patents:
______________________________________ French 1,377,998 U.S. 3,068,776 U.S. 2,187,767 U.S. 3,195,441 U.S. 2,241,108 U.S. 3,368,756 U.S. 2,551,965 U.S. 3,436,016 U.S. 3,027,090 U.S. 3,528,606 ______________________________________
Above-mentioned U.S. Pat. No. 3,436,016 particularly discloses a temperature responsive foundation ventilator construction having bimetallic spring operatively connected between a fixed shaft and movable shutters to provide for controlled movement thereof in response to predetermined temperature changes in the air passing through the shutter.
Although many such temperature responsive spring controlled louvered ventilators are known in the field of the art, there is an ever present need to provide a temperature-responsive, automatically controlled wall ventilator which can be more easily or economically manufactured to provide improved reliability of performance in use.